#define MD 998244353
ll@N,@M;mint a=1;if(M<?=N-M){if(N-M<MD<=N)a=0;else{ll E[]={1,467742124,703158536,849331177,183632821,786787592,708945888,623860151,442444797,339076928,916211838,827641482,982515753,303461550,466748179,669060208,789885751,915736046,189957301,934038903,728735046,774755699,649374308,602288735,492352484,958678776,943233257,148504501,352124178,569334038,927469492,343841688,432351202,700916755,170721982,8283809,875807278,931632987,330722936,603566523,391470976,157944106,826756015,278928878,178606531,522053153,175494307,16217485,310769109,430912024,970167731,302127847,960178710,607169580,211863227,918097328,664502958,598427325,415194799,38321157,375608821,557298612,497769749,114695383,77784134,629192790,339438380,348348875,713806860,526342541,671850855,414726935,844082152,412454739,351143550,868784407,834684152,186057224,996072584,619190001,24770542,765280770,513490122,468949120,867194196,866447292,937135640,560788103,308335177,703539315,252044620,119916775,298069903,43651994,148641017,730387621,856452172,74265901,626807500,980602375,42825068,348086475,162321900,207340584,151258454,461547160,320321845,361026143,882876292,842563318,257705870,158156446,292795459,984763947,917068833,811332379,782439665,944504775,298167161,141501910,155584237,149720256,71954352,666430555,580966229,884747116,616367471,918981127,310328833,724405658,383796145,256700166,487819118,642491144,181867555,524937737,222137750,445244561,79921588,253457448,405659726,260707689,740044210,654653354,229885020,230551611,616689587,939003921,565960348,904184966,133298693,859220865,186139683,765071679,247651638,451157944,929341123,503724944,768266737,142218056,910573117,274579400,151387843,212671109,815271666,406331931,154251304,642676789,570372925,976277122,442985463,928799971,817581666,797627351,100113334,877639265,541537097,434482347,300960222,270085755,481153328,236088097,686884498,323505794,897572220,900787550,277507290,157634146,892066519,616420589,46056764,697140618,592483685,896871487,896388868,106444279,115102765,191484323,62322499,434613622,426026852,378184205,194359325,415197585,965735328,598860936,653751428,942602959,475099103,642401460,77868208,464952529,549976420,705774928,635299526,704085554,809044086,670938184,799176916,58985566,402328281,182103192,921913660,674272214,428301920,520916749,127424638,296779896,166780239,19634060,95873539,708947606,532272305,980167862,7015847,370183454,45567119,866949818,374428494,25583689,351370758,835388325,232690098,42002598,17055285,985022727,214528454,122907290,793349516,609331634,87133548,248246624,448572380,502875867,183097664,536117329,170926160,381772251,37038194,374439881,94285547,880631489,452052533,739811514,675382782,587926712,179133902,694266603,338843576,281485671,813341519,616512705,222785194,382494725,471654428,961907947,442140830,702296161,548575377,388901073,19119024,545916498,947169254,801677200,377657430,634980290,246239186,13175103,239754689,656729178,364003283,646568868,584909084,690387116,452007054,131381944,908149670,807287523,802277179,745423153,893994782,197548253,376096720,105840336,687751559,170787791,928507410,620382696,446955151,139665212,882526402,494793004,107171423,753993075,467588754,207595897,269813018,941027990,856873596,717085190,245280646,792026805,548741735,523767341,637697735,261200153,89666563,344573088,15832984,558492246,825051585,923222974,826620400,558080789,657328927,991078225,706029275,738905108,401212366,980043233,895405022,597894231,636951913,947342478,786075225,395095090,188433847,121279219,860403973,396099425,240442489,521535558,280382318,58023116,735594008,8696133,477645338,223630480,816606673,680021043,362424474,181667447,504295826,332167472,766361494,992840497,417671938,376941230,11880047,275790726,106186450,150546053,966438917,431896075,158021876,734833661,328332504,632143386,962477966,638741189,728804571,753715698,20536106,45105841,271673172,982138522,604809222,199722980,211807634,478008419,194715230,246865373,316443541,869035744,202922168,245262975,136244583,650969410,566222746,55188168,495968583,571946805,188658038,353720239,830419870,669127165,86710835,810103736,630008035,764354348,209246227,277861984,725469211,151404581,894191013,775554083,634671016,170299187,471849450,575347258,505276194,636730506,40086858,386228700,789875034,998219457,359035788,843760715,864829665,794240359,241486050,48334220,583177582,714653706,617669563,132782021,779225352,333301287,520569296,508276228,689073648,573645847,200419842,911561316,310562870,204959007,879280837,762843188,103128368,133300147,648946778,287218789,662474952,587555465,105622721,648151526,517033362,729251452,850555187,708613432,874408867,345608416,690718720,10813958,42384375,882264058,825490058,252850511,652942840,202604098,277615259,862885671,582470925,190843016,534488148,187675153,911660635,377262012,642854978,359397276,712333871,580131409,841639861,925383257,213683380,25291651,974815450,32032244,119030165,443676106,555727293,170519648,171131074,839941962,789829593,140975543,845347712,303299112,530420097,857005350,249174130,224087061,311280308,404814306,567648772,766512373,470895965,294358155,625218604,89534510,513216330,78173719,22818060,254922573,292417477,415060121,208989124,960117615,570018845,237661008,442774488,871349246,161574942,548661451,313471555,448096394,587422360,987939533,254478574,113844945,268886375,927289435,664834607,983476167,390569280,363763327,935767957,159015901,508613041,134148582,127417680,484767855,825835285,43847241,972918293,151969014,768480291,729490470,76727400,384998943,648970509,764966281,391326774,585299643,661473977,530021579,368308424,81083443,981417794,185781362,169555925,934957641,56005264,296483160,853982963,489694611,73207251,20297311,431253211,168162850,36271383,689526671,397669110,705876730,785504919,764896820,936514026,350141918,784778738,682324919,140913543,862125900,723248565,369074340,146936534,226913694,277886748,856792647,13654547,141461269,255233971,979535193,747662027,452683681,338311679,399620140,306913085,817524367,333578440,943193170,387930488,964713035,554372227,524201507,267870305,698863503,695139108,399857384,830659092,479624682,594238820,768224890,956955770,940576967,920740072,282055556,621677930,847367415,619094041,432519599,192780811,912052381,263304046,114280963,307107320,956809356,118706101,836710721,356893069,427113038,55360495,892694364,443807400,568616581,130165565,732273554,778059496,95936679,629634134,383940143,474733431,271200931,253893765,65679204,670721645,268831988,225698685,424701963,654858732,405695790,894299102,797306377,464723449,647679843,730366154,956550665,898568348,313188681,661403769,346715295,358990430,868898456,719464962,978551995,772931269,255694712,379904456,393101377,130818973,810783770,78951115,608848341,941552927,523163696,581658405,188869913,161971620,114600913,300038465,126906968,572973411,118017645,806069307,430432761,310699012,989119052,282768145,557792692,611036992,427168405,84497995,529589599,967936672,416953197,549641787,787274930,514952744,646568513,39329263,765390776,831388678,299074396,102522509,886062498,598990751,553048069,305737423,388746841,13007805,3445560,568306294,109543305,847740132,746222360,454654676,748993028,222910140,861308982,390243513,692742883,789475199,153430402,299806798,913070840,881332402,245792511,618823409,1817990,897836424,726794141,700802042,472214481,97004031,479899815,573979309,752576644,374801082,599964908,894966385,178103304,12240556,393873628,855241924,305678131,971858774,281586141,87362107,41844894,175133514,276243521,997376957,260427125,439339251,64661516,362212695,186181824,423316311,267640938,299252572,810040987,857956827,758991665,207700847,399398818,747579039,814755712,298373935,307448236,42074518,982127624,538863790,528558929,96501138,813255509,611769398,710541518,408153968,675346745,970094012,791931126,811516976,618049736,264048084,209805699,909045292,645349311,416989597,590393407,320547207,342653696,860169617,856611053,475149267,124801433,547187333,466598598,266454901,554467907,868909135,199244107,548833449,20952517,234169026,117025205,804238552,205574540,590283297,822322644,866010856,477388420,935768507,424373916,951967787,344871828,133969287,937034425,309380768,666909962,726492795,996576193,883938945,869749688,313581344,65216237,88860786,208895640,888760811,854567609,328142793,121852766,928690075,135269006,333105486,502240551,573712984,397698082,935117672,718828733,440474396,335628894,184935718,788258676,646732201,68099895,167036421,362572358,787671392,666366534,193503119,74429287,132805884,796935846,124574194,926012440,147265585,722608579,526866610,452261307,990444071,4595579,147427028,774597449,678783012,568563934,383628463,68242206,163493293,352851801,123192034,529859554,14733470,565063217,178575398,580871309,135817500,313966456,647215844,118781836,106243172,796669460,48496927,772979683,715961917,546863206,601711799,644312478,629259662,738295002,692301787,149995411,864799423,284186171,246177326,268779154,86400350,518698490,321709079,946212693,800553099,865864136,244789848,386206318,851633075,713794602,131117952,280474884,243820970,820033654,399700655,825581574,443639603,774376660,362476217,552383080,436759518,538430048,965968656,150434699,563163603,352073025,840124972,152029247,902082055,770264937,747653807,934664232,541451013,807031739,854866728,503502641,283479207,297947602,488469464,205196166,381583984,108455782,570592132,363674728,134077711,356931610,887112858,273780969,443297964,650953636,402662299,894089640,71844431,33030748,208583995,597099208,671156881,875032178,998244352};auto f=[&](ll i){i%%=MD;mint t=E[i>>20];for(ll j=((i>>20)<<20)+1;j<=i;++j)t*=j;return t;};a=f(N)/f(M)/f(N-M);}}wt(a);