This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int maxn = 5e4 + 10;
string s[maxn];
int a[maxn];
unordered_map<string, int> mp[65];
int main(){
	ios_base::sync_with_stdio(false);
	int n, m;
	cin >> n >> m;
	for (int i = 0; i < n; i++){
		cin >> s[i];
		for (int j = 0; j < m; j++)
			if (s[i][j] != '?')
				a[i] += (1 << j);
	}
	ll answer = 0;
	for (int mask = 0; mask < (1 << m); mask++){
		for (int j = 0; j < n; j++){
			int me = (mask & a[j]);
			if (me != mask)
				continue;
			string now;
			for (int x = 0; x < m; x++)
				if (mask & (1 << x))
					now += s[j][x];
			mp[a[j]][now] ++;
		}
		for (int j = 0; j < n; j++){
			int me = (mask & a[j]);
			if (me != mask)
				continue;
			string now;
			for (int x = 0; x < m; x++)
				if (mask & (1 << x))
					now += s[j][x];
			for (int sub = 0; sub < (1 << m); sub++){
				if ((sub & a[j]) != mask)
					continue;
				answer += mp[sub][now];
			}
		}
		for (int j = 0; j < (1 << m); j++)
			mp[j].clear();
	}
	cout << (answer - n) / 2 << endl;
}
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