407

# include<stdio.h>
int main(void)
{
    int i,j;
    double item,sum;
sum=0;
for(i=1;i<=100;i++){
    item=1;
    for(j=1;j<=i;j++)
        item=item*j;
    sum=sum + item;
}
printf("1!+2!+...+100!=%e\n",sum);
return 0;
}