import java.io.IOException;
import java.io.InputStream;
import java.util.NoSuchElementException;

public class Main {
	public static void main(String[] args) {
		Main o = new Main();
		o.solve();
	}

	public void solve() {
		FastScanner sc = new FastScanner(System.in);
		long T = sc.nextLong();
		long A = sc.nextLong();
		long B = sc.nextLong();

		long g = gcd(A, B);

		long ans = (T - 1L) / A + (T - 1L) / B - (T - 1L) / (A / g) / B + 1L;

		System.out.println(ans);
	}
	// 最大公約数を計算する
	static long gcd(long a, long b) {
		while ( b != 0 ) {
			long tmp = b;
			b = a % b;
			a = tmp;
		}
		return a;
	}

	class FastScanner {
		private final InputStream in;
		private final byte[] buf = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;
		FastScanner( InputStream source ) { this.in = source; }
		private boolean hasNextByte() {
			if ( ptr < buflen ) return true;
			else {
				ptr = 0;
				try { buflen = in.read(buf); } catch (IOException e) { e.printStackTrace(); }
				if ( buflen <= 0 ) return false;
			}
			return true;
		} 
		private int readByte() { if ( hasNextByte() ) return buf[ptr++]; else return -1; } 
		private boolean isPrintableChar( int c ) { return 33 <= c && c <= 126; }
		private boolean isNumeric( int c ) { return '0' <= c && c <= '9'; }
		private void skipToNextPrintableChar() { while ( hasNextByte() && !isPrintableChar(buf[ptr]) ) ptr++; }
		public boolean hasNext() { skipToNextPrintableChar(); return hasNextByte(); }
		public String next() {
			if ( !hasNext() ) throw new NoSuchElementException();
			StringBuilder ret = new StringBuilder();
			int b = readByte();
			while ( isPrintableChar(b) ) { ret.appendCodePoint(b); b = readByte(); }
			return ret.toString();
		}
		public long nextLong() {
			if ( !hasNext() ) throw new NoSuchElementException();
			long ret = 0;
			int b = readByte();
			boolean negative = false;
			if ( b == '-' ) { negative = true; if ( hasNextByte() ) b = readByte(); }
			if ( !isNumeric(b) ) throw new NumberFormatException();
			while ( true ) {
				if ( isNumeric(b) ) ret = ret * 10 + b - '0';
				else if ( b == -1 || !isPrintableChar(b) ) return negative ? -ret : ret;
				else throw new NumberFormatException();
				b = readByte();
			}
		}
		public int nextInt() { return (int)nextLong(); }
		public double nextDouble() { return Double.parseDouble(next()); }
	}
}