Problem:
Score : 300 points

Problem Statement

You are given N positive integers a_1, a_2, ..., a_N.

For a non-negative integer m, let f(m) = (m\ mod\ a_1) + (m\ mod\ a_2) + ... + (m\ mod\ a_N).

Here, X\ mod\ Y denotes the remainder of the division of X by Y.

Find the maximum value of f.

Constraints

All values in input are integers.

2 \leq N \leq 3000

2 \leq a_i \leq 10^5

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the maximum value of f.

Sample Input 1

3
3 4 6

Sample Output 1

10

f(11) = (11\ mod\ 3) + (11\ mod\ 4) + (11\ mod\ 6) = 10 is the maximum value of f.

Sample Input 2

5
7 46 11 20 11

Sample Output 2

90

Sample Input 3

7
994 518 941 851 647 2 581

Sample Output 3

4527

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)


#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>

#ifndef U_L_LONG
typedef unsigned long long ULLONG;
#endif
#ifndef L_LONG
typedef long long LLONG;
#endif
template <class _T> static _T tp_abs(const _T& a) {
	//	usage:  tp_abs<type name>(a);
	return ((a < 0) ? (a * -1) : a);
}
template <class _T> static _T tp_min(_T a, _T b) {
	return a < b ? a : b;
}
template <class _T> static _T tp_max(_T a, _T b) {
	return a > b ? a : b;
}
template<class _T> static void get1int(_T& a) {
	const char* fmt = " %d";
	if (sizeof(_T) == sizeof(long long)) {
		fmt = " %lld";
	}

	if (scanf(fmt, &a) < 0) {
		printf("g1int Error\n");
	}
}
template<class _T> static void get2int(_T& a, _T& b) {
	const char* fmt = " %d %d";
	if (sizeof(_T) == sizeof(long long)) {
		fmt = " %lld %lld";
	}

	if (scanf(fmt, &a, &b) < 0) {
		printf("g2int Error\n");
	}
}
template<class _T> static void get3int(_T& a, _T& b, _T& c) {
	const char* fmt = " %d %d %d";
	if (sizeof(_T) == sizeof(long long)) {
		fmt = " %lld %lld %lld";
	}

	if (scanf(fmt, &a, &b, &c) < 0) {
		printf("g3int Error\n");
	}
}
template <class _T> static _T tp_gcd(_T first, _T second)
{
	_T num1 = first, num2 = second;
	_T remainder = 0, common = 0;

	if (!num1) return num2;
	if (!num2) return num1;

	while (!common) {
		remainder = num1 % num2;

		if (remainder == 0) {
			common = num2;
		}
		else {
			num1 = num2;
			num2 = remainder;
		}
	}
	return(common);
}
template <class _T> static _T tp_lcm(_T first, _T second) {
	_T gcd = tp_gcd<_T>(first, second);
	return first * second / gcd;
}


static void ABC103C_ModuleSummation();

#if 1
int main()
{
	ABC103C_ModuleSummation();
	fflush(stdout);
	return 0;
}
#endif

static void ABC103C_ModuleSummation()
{
	int N;
	get1int(N);

	auto seq = new ULLONG[N];
	ULLONG lcm = 1;
	for (int i = 0; i < N; i++) {
		get1int(seq[i]);
		lcm = tp_lcm<ULLONG>(lcm, seq[i]);
	}
	ULLONG fn = 0;
	for (int i = 0; i < N; i++) {
		fn += (lcm - 1) % seq[i];
	}
	printf("%llu\n", fn);

	delete[] seq;
}