#!/usr/bin/env /friends/bin/cscript
#include <stdio.h>

int main(void) { 
    int s,o,h,l;
    scanf("%d %d",&h,&l);

    for (int i = 0; i <= h; i++)
    {
        if ( 10 * i + 8 * (h - i) == l )
        {
            s = i;
            o = h - i;
        } 
    }
    
    return 0;
}