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import java.util.Scanner;
public class LastDigitOfFibSumAgain {
final static int FIB_PISANO_PERIOD_FOR_TEN = 60;
public static int getFibNModM(long n) {
long r = n % FIB_PISANO_PERIOD_FOR_TEN;
if (r == 0)
return 0;
int firstN = 0;
int secondN = 1;
int tempHolder = 1;
for (int i = 1; i < r; i++) {
tempHolder = (firstN + secondN) % 10;
firstN = secondN;
secondN = tempHolder;
}
return secondN;
}
public static int getLastDigit(long n) {
if (n <= 1)
return (int) n;
int result = getFibNModM(n + 2);
if (result == 0)
return 9;
else
return result - 1;
}
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
long m = in.nextLong();
long n = in.nextLong();
System.out.println(getLastDigit(m, n));
}
public static int getLastDigit(long m, long n) {
if (m == n)
return getFibNModM(n);
else {
int sumFn = getLastDigit(n);
int sumFm;
if (m <= 1)
sumFm = 0;
else
sumFm = getLastDigit(m - 1);
if (sumFn >= sumFm)
return sumFn - sumFm;
else
return sumFn - sumFm + 10;
}
}
}
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