P25176.go

// https://www.acmicpc.net/problem/25176

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var bw = bufio.NewWriter(os.Stdout)

func main() {
	defer bw.Flush()
	sc.Split(bufio.ScanWords)

	N := scanInt()
	result := 1

	for N > 0 {
		result *= N
		N--
	}

	fmt.Fprintln(bw, result)
}

func scanInt() int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}