#include <stdio.h>

int main() 
{
    int sign = 1;
    double sum=1, deno = 1, term;
    
    while ( deno <=100)
    {
    sign = -sign;
    term = sign * 1/deno;
    sum = sum + term;
    deno = deno +1;
    }
    printf ("%f\n",sum);
    return 0;
}