#include <stdio.h>
//#define long long ll
typedef long long ll;
ll myDiff(ll a, ll b){
    ll d = a - b;
    if (d >= 0)
        return d;
    else 
        return -1*d;
}
int main(){
    ll a, b;
    while (scanf("%lld %lld",&a ,&b) == 2)
        printf("%lld\n", myDiff(a, b));
}

#include <iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    string s;
    cin>>s;
    string as="ABC",bs="BABC",gs="CCAABB";
    int caa=0,cab=0,cag=0;
    for (int i=0;i<n;i++){
        if (s[i]==as[i%3])
            caa++;
        if (s[i]==bs[i%4])
            cab++;
        if (s[i]==gs[i%6])
            cag++;}
    int theMax=caa;
    if (theMax<cab)
        theMax=cab;
    if (theMax<cag)
        theMax=cag;
    cout<<theMax<<endl;
    if(caa==theMax)
        cout<<"Adrian"<<endl;
    if(cab==theMax)
        cout<<"Bruno"<<endl;
    if(cag==theMax)
        cout<<"Goran"<<endl;
}

#include <iostream>
using namespace std;
const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ_.,?";
const string morseCode[] = {
    ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..",   // A-I
    ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", // J-R
    "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--..",        // S-Z
    "..--", "---.", ".-.-", "----"                                   // _ . , ?
};
string encode(string message, string &morseConcat, string &lengths) {
    for (char ch : message) {
        for (int i = 0; i < alphabet.size(); ++i) {
            if (ch == alphabet[i]) {
                string code = morseCode[i];
                morseConcat += code;
                lengths += to_string(code.size());
                break;
            }
        }
    }
    return morseConcat;
}
string decode(string morseConcat, string lengths) {
    string result = "";
    int pos = 0;
    for (int i = lengths.size() - 1; i >= 0; --i) {
        int len = lengths[i] - '0';
        string chunk = morseConcat.substr(pos, len);
        for (int j = 0; j < 30; ++j) {
            if (chunk == morseCode[j]) {
                result += alphabet[j];
                break;
            }
        }
        pos += len;
    }
    return result;
}
int main(){
    string line;
    while (getline(cin, line)){
        string morseConcat = "", lengths = "";
        encode(line, morseConcat, lengths);
        cout << decode(morseConcat, lengths) << endl;
    }
}

#include <iostream>
using namespace std;
int main(){
    int C;
    cin >> C;
    for (int i = 0; i < C; i++){
        string s, t;
        cin >> s >> t;
        int cnt_0_to_1 = 0, cnt_1_to_0 = 0;
        int cnt_q_to_1 = 0, cnt_q_to_0 = 0;
        int cnt1_s = 0, cnt1_t = 0;
        int total = 0;
        for (int i = 0; i < s.size(); ++i){
            if (s[i] == '1') cnt1_s++;
            if (t[i] == '1') cnt1_t++;
                 if (s[i] == '0' && t[i] == '1') cnt_0_to_1++;
            else if (s[i] == '1' && t[i] == '0') cnt_1_to_0++;
            else if (s[i] == '?' && t[i] == '0') cnt_q_to_0++;
            else if (s[i] == '?' && t[i] == '1') cnt_q_to_1++;
        }
        if (cnt1_s > cnt1_t)
            total = -1;
        else{
            int swaps = min(cnt_0_to_1, cnt_1_to_0);
            int extra_flips = cnt_0_to_1 + cnt_1_to_0 - 2*swaps;
            total = swaps + extra_flips + cnt_q_to_0 + cnt_q_to_1;
        }
        cout << "Case " << i+1 << ": " << total << "\n";
    }
}