#include <stdio.h>

int min(int a, int b) {
    return (a < b) ? a : b;
}

int solution(int mainTank, int additionalTank) {
    // Calculate maximum transfers possible
    // We can transfer at most min(additionalTank, mainTank / 5) liters
    int maxTransfers = min(additionalTank, mainTank / 5);
    
    // Total fuel we can use = mainTank + transfers
    int totalFuel = mainTank + maxTransfers;
    
    // Distance = fuel * 10 km per liter
    return totalFuel * 10;
}

int main() {
    int mainTank, additionalTank;
    scanf("%d", &mainTank);
    scanf("%d", &additionalTank);
    int result = solution(mainTank, additionalTank);
    printf("%d\n", result);
    return 0;
}