The "first column" is every index x through x[m-1].
The "last row" is every index x[n-1] through x[n-1][m-1].
Make two more nested i/j for loops -- one that iterates over the last row, another that iterates over the last column. Keep a "min number so far" variable. Inside the loop, if the current x[i][j] is less than the 'min number so far', set it as the new min number.