#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>

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

    int up = 0;
    if(m >= 55){
        up = 1;
    }

    if(up){
        if(h == 23){
            h = 0;
        }else{
            h += 1;
        }
        m = (m+5) - 60;
    }else{
        m += 5;
    }

    int h0 = 0;
    int m0 = 0;
    if(h < 10){
        h0 = 1;
    }
    if(m < 10){
        m0 = 1;
    }

    if(h0 == 1 && m0 == 1){
        printf("0%d:0%d\n", h, m);
    }else if(h0 == 1 && m0 != 1){
        printf("0%d:%d\n", h, m);
    }else if(h0 == 0 && m0 == 1){
        printf("%d:0%d\n", h, m);
    }else{
        printf("%d:%d\n", h, m);
    } 
    
    return 0;
}