#include <iostream>
#include <stack>
using namespace std;
int main()
{
int n;
int s;
cin>>n>>s;
s--;
int matrix[n][n];
stack<int> st;
int counter=1;
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
cin>>matrix[i][j];
}
}
for(int j=0;j<n;j++)
{
if(matrix[s][j] == 1) st.push(j);
}
matrix[s][s]=1;
while(!st.empty())
{
int a=st.top();
st.pop();
if(matrix[a][a]!=1)
{
for(int j=0;j<n;j++)
{
if(matrix[a][j] == 1) st.push(j);
}
counter++;
matrix[a][a]=1;
}
}
cout<<counter<<endl;
}
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