You are given two strings, $S$ and $T,$ both of length $N.$ Both strings are made up

of digits. In a single move, you can select an index $K$ within the range $[0..$N$-2]$

and increase the digits $S[K]$ and $S[K+1]$ by $1.$ If a digit $9$ is increased, it

becomes $0.$

Is it possible to transform $S$ into $T$ by performing some $($possibly zero$)$

number of such moves? If so$,$ what is the minimum number of moves

needed?

Write a function:

int solution$($string &S$,$ string &T$)$;

that, given strings $S$ and $T,$ each of length $N,$ returns the minimum number of

moves needed to transform $S$ into $T.$ If it is not possible to obtain $T$ in this

way, return $-1.$

Examples:

For $S="13471"$ and $T="59604",$ the function should return $9.$

A valid sequence of moves could be as follows:

choose index $1$ and increase S$[1]$ and S$[2]$ two times. After these moves,

S becomes $"15671".$

choose index $3$ and increase S$[3]$ and S$[4]$ three times. After these

moves, S becomes $"15604".$