#include<stdio.h>
#include<stdlib.h>
main(){
    int V,T;
    char str[6],c;
    for(int i = 0;(c=getchar())!=' ';i++){
        if(c=='.'){i--;continue;}
        str[i] = c;
    }
    str[5] = '\0';
    V = atoi(str);
    scanf("%d",&T);
    printf("%d\n",V*T/10000);
}