import java.math.*;

// マーチンの公式を使用
// pi = 16*{1/5-1/(3*5^3)+1/(5*5^5)-1/(7*5^7)...}
//      -4*{1/239-1/(3*239^3)+1/(5*239^5)-1/(7*239^7)...}

class pi {
	static int scale = 30;
	static int loop = 1000;
	
	public static void main(String[] args) {
		BigDecimal bdZero = new BigDecimal(BigInteger.ZERO, scale);
		BigDecimal bdOne = bdZero.add(new BigDecimal(1));
		BigDecimal bdFive = bdZero.add(new BigDecimal(5));
		BigDecimal bd239 = bdZero.add(new BigDecimal(239));
		BigInteger biFive = new BigInteger("5");
		BigInteger bi239 = new BigInteger("239");
		
		BigDecimal v1 = bdOne.divide(bdFive, BigDecimal.ROUND_HALF_EVEN);
		BigDecimal v2 = bdOne.divide(bd239, BigDecimal.ROUND_HALF_EVEN);
		for (int i = 1; i <= loop; i++) {
			int n = i * 2 + 1;
			BigInteger biN = new BigInteger("" + n);
			
			BigInteger i1 = biFive.pow(n);
			BigInteger i2 = bi239.pow(n);
			i1 = i1.multiply(biN);
			i2 = i2.multiply(biN);
			BigDecimal t1 = bdOne.divide(new BigDecimal(i1), BigDecimal.ROUND_HALF_EVEN);
			BigDecimal t2 = bdOne.divide(new BigDecimal(i2), BigDecimal.ROUND_HALF_EVEN);
			
			if ((i % 2) == 0) {
				v1 = v1.add(t1);
				v2 = v2.add(t2);
			} else {
				v1 = v1.subtract(t1);
				v2 = v2.subtract(t2);
			}
		}
		v1 = v1.multiply(new BigDecimal(16));
		v2 = v2.multiply(new BigDecimal(4));
		v1 = v1.subtract(v2);
		System.out.println("pi:" + v1.toString());
	}
}