小玉游泳淹死了

# include <stdio.h>
# include <math.h>
int main(void)
{
    double a, b=2; //a表示需要游多远，b表示游了多远
    int c=1;        //c表示第几步
    scanf ("%lf", &a);
    while (b < a)
    {
        b = b + 2 * pow(0.98, c-1);
        c+=1;
    }
    printf ("%d", c);
    return 0;
}