改了几次都是30

#include <iostream>
int main() {
	using namespace std;
	long long count=0;
	int b[10],n,m;
	cin >> n >> m;
	char c[2001][2001];
	for (int i = 0; i < n; i++)
		for (int j = 0; j < m; j++) {
			cin >> c[i][j];
			switch (c[i][j]) {
				case '1':
					b[0]++;
					break;
				case '2':
					b[1]++;
					break;
				case '3':
					++b[2];
					break;
				case '4':
					++b[3];
					break;
				case '5':
					++b[4];
					break;
				case '6':
					++b[5];
					break;
				case '7':
					++b[6];
					break;
				case '8':
					++b[7];
					break;
				case '9':
					++b[8];
			}
		}
	for (int a = 0; a < 9; a++)
		count += b[a] * (b[a] - 1);
	for (long long i = 0; i < n; i++)
		for (long long j = 0; j < m; j++) {
			if (i<n-1&&c[i][j] == c[i + 1][j])
				count--;
			if (i>0&&c[i][j] == c[i - 1][j])
				count--;
			if (j<m-1&&c[i][j] == c[i][j + 1])
				count--;
			if (j>0&&c[i][j] == c[i][j - 1])
				count--;
		}
	cout << count;
	return 0;
}