Matrix Multification

import java.util.Scanner;

public class MulMatrix {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("enter matrix size");
int r = scanner.nextInt();
int c = scanner.nextInt();
int[][] a = new int[r][c];
int[][] b = new int[r][c];
int[][] sum = new int[r][c];
System.out.println("Enter first matrix values");

for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a.length; j++) {
System.out.println(a[i][j] + "th position value");
a[i][j] = scanner.nextInt();
}

}
System.out.println("Enter second matrix values");
for (int i = 0; i < b.length; i++) {
for (int j = 0; j < b.length; j++) {
System.out.println("enter " + b[i][j] + "these position value");
b[i][j] = scanner.nextInt();
}

}
for (int i = 0; i < sum.length; i++) {
for (int j = 0; j < sum.length; j++) {
sum[i][j] = a[i][j] * b[i][j] + a[i][j] * a[i][j];
}

}
System.out.println("Display values");
for (int i = 0; i < sum.length; i++) {
for (int j = 0; j < sum.length; j++) {
System.out.print(sum[i][j] + "\t");
}
System.out.println();

}
}

}