let input = ['4','1','1','1','1'];
let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);


let n = +gets();
let a= +gets(); // number of values
let b= +gets();
let c= +gets();
let d= +gets();
let sum = c;


for ( let i= 0; i <= n; i++) {
  sum = a+b+c+d
}
print((sum/n).toFixed(2))