include <stdio.h>
int main() {
int x;
int y;
scanf("%d", &x);
scanf("%d", &y);
int sum = 0;
while (x <= y) {
if (x % 4 == 0 && x % 100 != 0) {
sum = sum + 1;
} else if (x % 400 == 0 && x % 100 == 0) {
sum = sum + 1;
}
x++;
}
printf("%d", sum);
return 0;
}