con questo programmino, mi restiuisce un errore in "a=br.readLine();"

// somma numeri
import java.io.*;

class MioProgramma
{
public static void main(String[] args)
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int a,b,c;
a=br.readLine();
b=br.readLine();
c=a+b;
System.out.println(c);
}
}