#include <stdio.h>

int main(int argc, char *argv[], char * env[])
{
        int first, second;
        int answer;

        scanf("%d %d", &first, &second);
        answer = (50 * first) + ((50 * first) / (0.8 + (0.2 * second)));
        printf("%d\n",answer);

        return 0;
}