return type is incompatible error

package interfaces;
interface Left
{
    public void m1();
}
interface Right
{
    public int m1();
}
public class INCissues implements Left,Right
{
    public void m1()
    {
        ......
    }
    public int m1()  //error
    {
        .......
    }
// In single class two same method signature not allow
}