#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#define rep(E, F) for (E = 0; E < (F); E++)
int max(int a, int b) { if (a < b) return b; return a; }
int get_int();

int main()
{
	int i, j, n = get_int(), t = 0, s = 0, r, x, y;
	int a[n];
	rep(i, n) t += a[i] = get_int();
	rep(i, n) s = max(s, a[i]);
	rep(i, n) if (s == a[i]) break;
	r = i;
	t -= s;
	if ((t + s)%2 == 1 || s > t) { printf("NO\n"); return 0; }
	printf("YES\n");
	x = y = 0;
	while (s != t)
	{
		while (a[x] == 0 || x == y || x == r) x++;
		a[x]--;
		while (a[y] == 0 || x == y || y == r) y++;
		a[y]--;
		printf("%d %d\n", x + 1, y + 1);
		t -= 2;
	}
	x = 0;
	while (t != 0)
	{
		while (a[x] == 0 || x == r) x++;
		printf("%d %d\n", r + 1, x + 1);
		a[x]--;
		t -= 1;
	}

	return 0;
}

int get_int()
{
	int ret = 0;
	char c = getchar();
	int sgn;

	while (1)
	{
		if (c == EOF) return EOF;
		if (c >= '0' && c <= '9') { sgn = 1; break; }
		if (c == '-')
		{
			c = getchar();
			if (c < '0' || c > '9') continue;
			sgn = -1;
			break;
		}
		c = getchar();
	}

	while (1)
	{
		ret = ret*10 + c - '0';
		c = getchar();
		if (c < '0' || c > '9') return sgn*ret;
	}
}