代码：

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, sum = 0;
int num[105][105] = {0};
int visit[105][105] = {0};
void dfs (int a, int b) {
    visit[a][b] = 1;
    int xcp[4] = {0, -1, 0, 1};
    int ycp[4] = {1, 0, -1, 0};
    for (int i = 1; i <= n; i++) {
        int dx = a + xcp[i];
        int dy = b + ycp[i];
        if (dx >= 1 && dx <= n && dy >= 1 && dy <= m && visit[dx][dy] == 0 && num[dx][dy] > 0) 
            dfs(dx, dy);
    }
    return;
}
int main () {
    char s;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            cin >> s;
            num[i][j] = s - '0';
        } 
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            if (num[i][j] > 0 && visit[i][j] == 0) {
                dfs(i, j);
                sum++;
            }
        }
    cout << sum << endl;
    return 0;
}