Generator point G several times

if in a curve y2 mod p = x3 + 7 mod p (ecdsa-secp256k1)

p = 115792089237316195423570985008687907853269984665640564039457584007908834671663

G = 55066263022277343669578718895168534326250603453777594175500187360389116729240.326705100207588169780830850304318447126535437544351235353535353835353835353835353835353835353835353835353835353835353835353835353535383535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353538

nG = 21505829891763648114329055987619236494102133314575206970830385799158076338148,98003708678762123368324050308090909090909090909090908908328328328388388388388

2 ng = 72488970228380509287422715226575535698893157273063074627791787432852706183111,62070622898698443831883535403436258712770888294397026493185421712108624767191

How do i find & # 39; n & # 39;