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

int main(void)
{
	int ab[2];
	char str[32], *ch;
	fgets(str, sizeof(str), stdin);
	ch = strtok(str, " \n");
	for (int i = 0; i < 2; i++) {
		if (ch == NULL) break;
		else ab[i] = atoi(ch);
		ch = strtok(NULL, " \n");
	}
	printf("%d\n", 50 * ab[0] + (int)(50 * ab[0] / (0.799 + 0.2*ab[1])));
	return 0;
}