#include <stdio.h>

int main() { float chengji[5]; scanf("%f",&chengji[0]); scanf("%f",&chengji[1]); scanf("%f",&chengji[2]); scanf("%f",&chengji[3]); scanf("%f",&chengji[4]); float sum= 0; int n = 4; while(n != -1) { sum = sum + chengji[n]; n--; } sum = sum / 5; printf("%.1f",sum); return 0; }