#include int n[1000]; int m[1000]; int main() { int c, d , i ; double sum; scanf("%d",&c); n[1] = 2 , m[1] = 1 , sum = 0 ; for ( i =1;i<=c;i++) { sum+=(1.0*n[i]/m[i]); d = m[i]; m[i+1] = n[i]; n[i+1] = n[i] + d ; } printf("sum=%.2fn",sum); return 0; }