Programming Olympiad N participants arrived at the AFM Olympiad. As a result of the survey, the jury members found that a participants encode in C, b in Python, c in Pascal, x simultaneously know C and Python, y-Python and Pascal, z-C and Pascal. Having the values n, a, b, c, x, y, z set the number of participants who program in three programming languages.

Input data
One line contains seven integers n, a, b, c, x, y, and z, whose values do not exceed 100.

Output data
Print the number of participants who program in three programming languages.