#include <stdio.h>
#include <stdlib.h>
int main() {
char number[10];
int count = 0;
int myNum;
int max = -1;
while(fgets(number,10,stdin) != NULL) {
myNum = atoi(number);
if (count != 0) {
if (max < myNum) {
max = myNum;
};
};
++count;
};
if (max > 0) {
printf("%d",max);
}
else {
printf("None");
};
return 0;
};
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