#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    string s, t;
    cin >> s >> t;
    int h1 = (s[0] - '0') * 10 + s[1] - '0',
    h2 = (t[0] - '0') * 10 + t[1] - '0';
    int m1 = (s[3] - '0') * 10 + s[4] - '0',
    m2 = (t[3] - '0') * 10 + t[4] - '0';
    int cnt = 0;
    if(h1 <= h2){
        cnt += h2 - h1;
    }else{
        cnt += 24 - h1 + h2;
    }
    if(m1 > m2){
        cnt--; 
        cnt += 60 - m1 + m2;
    }else{
        cnt += m2 - m1;
    }
    cout << cnt;
    return 0;
}