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

int main(void)
{
    long long A;
    long long ans;
    double B;
    long long tA;
    int tB;
    scanf("%lld", &A);
    scanf("%lf", &B);
    tA = (long long)(A / 100);
    tB = (int)(100 * B);
    if (100 * B - tB > 0.5)
    {
        ++tB;
    }
    ans = tA * tB + (long long)(((A - tA * 100) * tB) / 100);
    printf("%lld", ans);
    return 0;
}