PROGRAMMING:Calculate 1+ 2！+...+ n!

Known factorial function as follows, using this function, programming calculation and output 1+ 2!+...+ n! The value of.
Where n is entered by the user from the keyboard.
```
unsigned long Fact(unsigned int n)
{
int i;
unsigned long result = 1;
for (i=2; i<=n; i++)
result *= i;
return result;
}
```
###Input format:
The user enters the value of positive integer n from the keyboard.
###Output format:
Output the result of calculation in the form of output sample.
###Input example:
```in
five
```
###Output example:
```out
sum=153
```







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