We have to calculate m + n - 2 C n - 1 here which will be ( m + n - 2 ) ! / ( n - 1 ) ! ( m - 1 ) ! path = 1 ;
for i in range ( n , ( m + n - 1 ) ) : NEW_LINE INDENT path *= i ; NEW_LINE path //= ( i - n + 1 ) ; NEW_LINE DEDENT return path ; NEW_LINE