#include <stdio.h>
int main(void) {
double x,y;
int i,j;
for(i=20,x=0.0;i<41;i++){
for(y=1.0,j=1;j<=i;j++){
y*=(double)((40-j+1)/(double)j);
}
for(j=0;j<40;j++)y*=0.5;
x+=y;
}
x*=x;x*=0.2;
}
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