#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
using ll = long long;
using namespace std;
const int INF = 1e9;

int main() {
    int m, h;
    scanf("%d:%d", &h, &m);

    if(m>=55){
        m += 5;
        m %= 60;
        ++h;
    }
    else{
        m += 5;
    }

    printf("%02d:%02d\n", h % 24, m);

    return 0;
}