#include <iostream>
using namespace std;
int main() {
int nocalif=7, i;
double calif[nocalif], s=0.0, prom;
for(i=0; i<nocalif; i++){
cin>>calif[i]; }
for(i=1; i<nocalif; i++){
s=s+calif[i]; }
prom=s/nocalif;
cout<<prom;
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwoKaW50IG1haW4oKSB7CglpbnQgbm9jYWxpZj03LCBpOwoJZG91YmxlIGNhbGlmW25vY2FsaWZdLCBzPTAuMCwgcHJvbTsKCWZvcihpPTA7IGk8bm9jYWxpZjsgaSsrKXsKCQljaW4+PmNhbGlmW2ldOwl9Cglmb3IoaT0xOyBpPG5vY2FsaWY7IGkrKyl7CgkJcz1zK2NhbGlmW2ldOyB9CgkJcHJvbT1zL25vY2FsaWY7CgkJY291dDw8cHJvbTsKCXJldHVybiAwOwp9Cg==